Abstract: An optimization model is presented for the control of saltwater intrusion in the Jakarta groundwater basin. A quasi three dimensional, finite difference simulation model is used to predict freshwater and saltwater heads and the location of the interface in the multiple layer aquifer system. These hydraulic response equations are incorporated in an optimal control model of the groundwater basin. The optimization model minimizes the total volume of saltwater in each aquifer of the groundwater system; the control variables of the model are the location and magnitude of groundwater pumping and recharge. The model is required to satisfy the current water demand in the basin. The optimization model is solved using MINOS, a projected Lagrangian algorithm. Preliminary planning results are presented.